1. Field
The invention relates to a mask and a method of manufacturing the same.
2. Description of the Related Art
Flat panel display devices are replacing cathode-ray tube display devices, due to their lightweight and thin characteristics. Typical examples of the flat panel display devices include liquid crystal display devices (“LCDs”) and organic light-emitting diode display devices (“OLEDs”). OLEDs have excellent brightness and viewing angle characteristics as compared to LCDs, and can be realized as ultra-thin display devices because they do not require a separate light source such as a backlight unit.
OLEDs use a phenomenon in which electrons and holes injected into an organic thin film from a cathode and an anode are recombined to form excitons, and light having a specific wavelength is emitted by energy generated from the excitons.
OLEDs are classified into a passive-matrix type and an active-matrix type according to a driving method. Active-matrix OLEDs include a circuit using a thin-film transistor (“TFT”).
Passive-matrix OLEDs are easy to manufacture because their display region is constructed in a simple matrix of anodes and cathodes. However, the passive-matrix OLEDs are restricted in application fields of low-resolution and small displays due to problems with resolution, an increase in driving voltage and a decrease in material duration. Active-matrix OLEDs can provide stable luminance due to a constant current supplied to each pixel using a TFT located at each pixel of a display region. With their low power consumption, the active-matrix OLEDs can be implemented as high-resolution and relatively large-sized displays.
To realize a full-color OLED, red, green and blue light-emitting layers may be formed using a laser induced thermal imaging (“LITI”) method among various methods. In the LITI method, a laser beam emitted from a laser source is patterned using a mask having patterns, and the patterned laser beam is irradiated onto a donor substrate which includes a base substrate, a light-to-heat conversion layer and a transfer layer (e.g., an organic layer including a light-emitting layer), such that part of the transfer layer can be transferred onto a device substrate. Accordingly, organic film layer patterns including the light-emitting layer are formed on the device substrate. The LITI method is advantageous in that it can finely pattern each light-emitting layer and is a dry-etching process.
The mask having the patterns includes transmissive regions which transmit laser light and non-transmissive regions which do not transmit laser light.